I TOTALLY suggest the following setup, based on a LOT of testing...
Radio -
Eurgle 2.4Ghz 3ch receiver (very small, about 22mm x 12mm x 8mm!) plus the 3ch Eurgle TX is awesome! 8 model memory plus LCD screen. About $80 w/rcvr. EBay or R2Hobbies.com
ESC -
Exceed Novatech B4715 25A brushless car ESC; just fits inside the chassis along with the rcvr. Very bomber! About $30 on Hobbypartz.com
Servo -
Hobbycity Hextronix 14G metal gear mini servo - from Hobbycity.com, very lightweight, very fast (about .08sec) and great torque. About $12 Hobbycity.com
Motor -
GWS Electrifly 2030 5200kv brushless. VERY fast, almost too fast yet very smooth and controllable. Like a V8 engine in a Volkswagen. EXACT same size as the stock Kyosho motor (20mm dia x 30mm length) so drops right in. About $30 Towerhobbies.com
I did notice that I didn't have to replace any of my gearbox plastic? Maybe because I'm running bearings everywhere which gets rid of most friction. All my gears are stock plastic even with brushless.
I replaced all of the large phillips screws with 4-40 x 3/8 stainless steel socket screws (mcmaster.com), since the phillips screws strip after a few rebuilds. I dont do too much aluminum, since it adds weight, and doesnt flex under impact like plastic does, instead it bends which then needs replacement. Plastic cheaper to replace anyways
Definitely replace swing arm with aluminum though, if you run brushless.
Venom medium compound front and rear tires for better grip. Use Venom rear tire insert. (Towerhobbies.com).
Front tire can be filled with a strip of soft gray foam (not dense black stuff), since flywheel doesnt allow Venom insert to fit.
Run lightweight front wheel flywheel for good handling and a little faster steering than stock flywheel (2wheelhobbies.com)